Telephone receiver



July 24, 1928'. 1,678,200

M. C. RORTY ET AL TELEPHONE RECEIVER 7 Filed Jan. 5, 1926 I! Ill /6 i 25JNVEMORs:

M. c. RORTY J c. POTTER it; ,II'I'TORNEYS' Patented July 24, 1928.

UNITED STATES ASSIGNORS, BY MESNE ASSIGNMENTS,

PATENT OFFICE.

MALCOLM o. RORTY, or PARIS, FRANCE, Ann JOHNC. POTTER, or MADRID; SPAIN,

TO WESTERN ELECTRIC COMPANY, INCOR- PORATED, OF NEW YORK, N. Y., ACORPORATION OF NEW YORK.

T ErHoNE RECEIVER.

Application filed January This invention relates to telephone receivers,and has for its general Object the provision of a'new and improvedstructure which is simple in construction, and eflicient andsatisfactory in operation. 7

The characteristic features of the inven tion will be hereinafterdescribed in connection with the accompanying drawing in which is showna watch-case receiver having the invention embodied therein, although itis to be understood that it may equally well be embodied in receivers ofother types.

In the drawing, Fig. 1 is a sectional elevation on a plane passingthrough the a'x1s of the receiver; and Fig. 2 is a plan view, with theear-piece portion of the casing removed, showing the internal partsofthe receiver.

Referring to the drawing, the internal" parts of the receiver are shownas mounted in a casing, made of bakelite or OlillGP'SHlllable material,comprising a cup-shaped back portion 5 and an ear-piece 6 of formsclearly shown in the drawing, these parts being se' cured to one anotherby cooperating threaded portions indicated at 7. The permanent magnetstructure of' the receiver comprises an iron or steel cupshaped portion9, and an iron or steel mushroom-shaped portion 10 which is secured tothe middle of the inside of the portion 10 by a screw 12.0r in any othersuitable manner.

It will be. understood that the magnetic flux, due to this permanentmagnetic structure, passes across the annular gap between the edge 14;of the mushroom-shaped magnet portion 10, and the edge 15 of thecupshaped portion 9 of the permanent magnet. This gap is bridged by apole piece in the form of a soft iron annular cup 17, arranged betweenthe upturned edge 15 of the cupshaped magnetic portion 9 and the edge 14of the mushroom-shaped magnetic portion .10, except for the fact that agap of low magnetic permeability is introduced by mea ne of a ring 18 ofbrass or other substantially non-magnetic material interposed betweenthe inner upturned edge of the annular cup 17 and the edge 14 of themushroomshaped magnetic portion 10. The mushroom-shaped magnetic portion10, the brass ring 18 and the annular cup 17 are preferably sweated 5,1926. Serial No. 79,294.

together; and their relations'to oneeanother will be understood fromFig. 1. Thiscon struction' facilitates the accurate determina tio n, bygrinding operations, of the distance between the plane of the topface ofthe mushroom-shaped portion 10, and the plane of the top of the outeredge of'the annular cup 17," this being an importantmatter, as

thereto by a cap 21 through which passes a screw 22 which extendsthrougha hole in the center of the diaphragm QO-and enters the threadedhole in the magnet" portion 10 with which the other end of the screw 12cooperates. As clearly shown in Fig. 1. the cap 21 is recessed on itsbottom, soas to form a downwardly extending flanged edge whichcooperates with the diaphragm above the outer edge 14. of themushroom-shaped magnet portion 10. In this manner, the diaphragm12O isso held that its edge, and not its center, is free to vibrate. The coil25 of the wire carryingthe talking current is mounted within the softiron annular cup 17, the ends 26 of said coil being brought out throughholes in the annular cup 17, the cup-shaped magnet portion 9 and theback portion 5 of the casing, or being secured to terminals extendingfrom the outside of the casing portion 5 in a well known manner. Thecoil 25, being of large diameter. can be of comparatively coarse wire,and still have ade-. quate impedance.

the varying magnetic flux. due to the'coil 25,

In the operation of the telephone receiver,

swings the magnetic fiuX, due to the permanent magnetic structure, baclsand forth across the gap introduced by the brass ring 18 and the air gapbetween the outer edge of the annular cup 17 and the edge of thediaphragm 20 This, of course, causes the edge of the diaphragm 20 tovibrate, with consequent production of sound waves.

It will be apparent that thereceiver struc ture which forms the subjectof this invention, is highly efilcient because the magnetic flux due tothe permanent magnetic struc ture is swung back and forth, and is notvHavingdescribed the invention, what is claimed is:

1. In a telephone receiver, a permanent,

magnet structure providing an annular gap,

a soft iron pole piece located in said annular gap, a c011 cooperatingwith said pole 131608,

and. a diaphragm rigidly supported at its central portion and having itsedge-extending into cooperative relation with sand pole piece. v

2. In a telephone receiver, a permanent magnet structure providing anannular gap, a soft iron annular cup cooperating with said .magnetstructure and located in said annular gap, a coil located in saidannular cup,and a diaphragm rigidly supported at its central portionandhaving its edge extending into cooperative relation with said,

annular cup.

3. In a telephone receiver, a permanent magnet structure providing anannular gap, at softiron annular cup located in said gap and cooperatingwith said permanent magnet structure, a spacing member'ot substantiallynonmagnetic material interposed between one edge of said annular cup andsa d magnetic structure, a diaphragm rigidlysecured at a central portionto said magnetic structure and having its edge in cooperative relationto the other edge ofzsaid annular cup, and a coil located in saidannular cup.

4. In a telephone receiver, a permanent magnet structure. comprising acup-shapedv member and a mushroom-shaped member secured to the center ofsaid cup-shaped member, a soft iron annular cup located in the annularspace between said magnet members, a coil located in said annular cup, a

diaphragm extending over the top of said mushroom-shaped magnet memberand in cooperative relation to one edge of said annular cup, and meansfor rigidly securing the central portion of said diaphragm to saidmushroom-shaped magnet member.

5. In a telephone receiver, a permanent magnet structure comprising acup-shaped memberfand a mushroom-shaped member secured to the centerofsaid cup-shaped member, a soft iron annular cup located in the annularspace between the edges of said magnet members, a diaphragm extendingover the top of'saidmushroom-shaped member andin cooperative relation tothe outer edge of said annularcup, a cap extending over the centralportion of said diaphragm, and means for securing said. cap to saidmushroom-shaped member in clamping engagement with said diaphragm.

6, In atelephone receiver,'a cup-shaped permanent magnet, a plurality ofannular magnetic poles for. said magnet, a coil for said poles, adiaphragm, and means forsupporting said diaphragm so that the periplnery thereof is free to vibrate.v r

7. In combination, a circular magnet, 21 channel-shaped, circularmember, the flanges ofwhich serve asmagnetic poles for said magnet, acoil positioned between the flanges of said member, and means forsupporting said diaphragmat points removed from its periphery, so thatthe periphery is free to vibrate.

8. In combination, a magnet, a diaphragm, a circular, supporting membertherefor of smaller diameter than said diaphragm and forming one pole ofsaidmagnet, and an annular channel-shaped memher, the flanges of saidmember constituting poles of opposite polarity to that of said circularmember and a coilin said channel.

9. In a telephone receiver, a circular magnet, a vibratile member,supporting means for said member, said means. constituting one pole of,said magnet and an annular shaped member, portions thereofformingmagnetic poles, said poles being spaced relative to said vibratilemember and said supporting means to formparallel flux paths.

In testimony whereof we have affixed our signatures to thisspecification.

'MALcoLM c. nonrr.

JOHN G. POTTER,

